A Recent Advance in Understanding the Universe

Science keeps growing. One of the main ways our knowledge of the Universe increases is when scientists build a better instrument, a new tool that can observe things we could never see before. The NSW syllabus asks you to investigate how a recent advancement in science has increased knowledge of the world and the Universe (SC4-OTU-01). In this lesson, that recent advance is the James Webb Space Telescope.

The idea works like a chain:

• A new instrument (better technology) is built.
• The instrument makes new observations that were impossible before.
• Those observations build new knowledge, and sometimes they even change the models scientists use to explain the Universe.

This is exactly the nature-of-science idea from the rest of this unit. Better tools lead to better observations, and better observations lead to better understanding. The telescope does not decide what is true on its own; it gives scientists the evidence they need to test and improve their ideas.

The James Webb Space Telescope, often shortened to JWST, is the most powerful space telescope ever built. Here are the key facts you should know.

• Launched: 25 December 2021, on a rocket from South America. It was folded up to fit inside the rocket, then it slowly unfolded in space like origami.
• First images: the first full-colour images were released in July 2022, and they amazed scientists around the world.
• Infrared eyes: JWST sees in infrared light, a kind of light our eyes cannot see. Infrared light passes through dust, so the telescope can peer inside the dust clouds where new stars and planets are forming.
• Its parking spot: JWST sits about 1.5 million kilometres from Earth, at a special place called the second Lagrange point. That is about four times further away than the Moon, and it keeps the telescope cold and steady so it can take clear pictures.

Because JWST is so powerful and sees in infrared, it has let scientists look at three kinds of things in a brand new way: the most distant and earliest galaxies, the dust clouds where stars and planets are born, and the atmospheres (the air) around planets that orbit other stars, called exoplanets. Each of these is new knowledge that older telescopes could not give us.

Let us look more closely at the three big areas where the James Webb telescope has increased our knowledge.

• The earliest galaxies: light takes time to travel across space, so looking far away is also looking back in time. JWST can see some of the most distant galaxies, which formed not long after the Universe began. This helps scientists understand how the very first galaxies grew.
• How stars and planets form: by looking inside glowing dust clouds, JWST has watched new stars and planets taking shape. This builds knowledge about how our own Sun and Earth may have formed long ago.
• The air on other worlds: when a planet passes in front of its star, some starlight shines through the planet's atmosphere. JWST can read that light to work out which gases are in the air of an exoplanet. This helps scientists ask whether any of these distant worlds could support life.

Notice the pattern. The new instrument made new observations, and those observations built new knowledge. None of this was possible before the telescope was built. That is how a single recent advance can increase what humans know about the Universe.

JWST is run mainly by space agencies in the United States and Europe, but Australia is a world leader in a different way of studying the Universe: radio astronomy. Instead of collecting visible or infrared light, radio telescopes collect radio waves from space. These are another kind of light that our eyes cannot see.

• The Parkes radio telescope (Murriyang): in central New South Wales, this famous dish helped send the live television pictures of the 1969 Moon landing back to the world. Its name, Murriyang, comes from the Wiradjuri People, the Traditional Custodians of the land it stands on.
• The Square Kilometre Array (SKA-Low): a huge new radio telescope is being built in remote Western Australia, on Wajarri Country. When finished, it will be one of the most powerful radio telescopes in the world, made of thousands of small antennas working together.

Australia's clear skies and quiet, remote areas, far from city radio signals, make it a great place for radio astronomy. So while JWST looks at the Universe in infrared light from space, Australian scientists help study it in radio waves from the ground. Together, different instruments give a fuller picture of the Universe.

JWST is our lead example, but it is not the only recent advance that has grown our knowledge of the Universe. Here are two more, each made possible by clever new instruments.

• The first image of a black hole (2019): a team using the Event Horizon Telescope joined together many radio telescopes from around the world to act like one giant telescope. In 2019 they released the first ever picture of a black hole, showing a dark centre ringed by glowing gas. Before this, no one had photographed a black hole.
• The detection of gravitational waves (2015): in 2015, scientists using detectors called LIGO measured tiny ripples in space itself, made when two black holes crashed together far away. These ripples are called gravitational waves. Detecting them gave scientists a completely new way to observe events in the Universe.

Each of these is the same story as JWST. A new instrument made a new observation possible, and that observation built new knowledge. Recent advances like these are how science keeps increasing what we understand about the world and the Universe.